Explosion-alleviator for internal-combustion engines



B. BANNISTER. EXPLOSION ALLEVIATORFOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED FEB. 25,1920- 1,360,074. Patented Nov. 23,1920.

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A TTORNE Y B. ammsm. EXPLOSiON ALLEVIATOR-FOR mum/u comau'snou mamas. IAPPLICATION FILED FEB. 25, 1920. 074 Patented Nov. 23, 1920.

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INVENTOR A TTORNE Y UNITED STATES PATENT OFFICE.

BRYANT BANNISTER, 0F PITTSBURGH, PENNSYLVANIA.

EXPLOSION-ALLEVIATOK FOR INTERNAL-COMBUSTION ENGINES.

Specification of Letters Patent. Patented N 23 192() Application filedFebruary 25, 1920. Serial No. 361,225.

possible the employment of a high compression without the occurrencewithin the cyl inder of a correspondingly high explosion pressure at anyinstant.

Another object of the invention is to provide means which smooth out thehigh pressure impulse, incident to the explosion of the combustiblecharge, over an increased portion of the power stroke of the enginepiston; thus not only damping the sharp initial rise in pressure duringcombustion of the charge, but also preventing the usual abrupt drop inpressure during expansion.

A further object of the invention is to provide valve means which serveto secure the full effect of the pressure alleviation and conservationby operating with sufficient speed after ignition of the combustiblecharge to permit expansion into an auxiliary clearance space during theprogress of combustion.

A practical advantage foregoing is, that internal combustion engines maybe readily modified so as to materially increase compression and securea substantial gain in available power and in economy, without greaterstress in, or shock to the engine parts. Thus by decreasing theclearance space within the cylinder, or cylinders, of the engine, or byincreasing the piston displacement without increasing the is applied.

derived from the ance itself loses all value.

cure economy in manufacture by lessening the amount oi metal 111 thecylinder, or cylinders, oi the engine to which the device In theaccompanying drawings Figure 1 1s a vertical cross section through oneembodiment of the invention; Fig. 2 is a detail view of a modificationthereto; Fig. 3 is a vertical cross section through another embodimentof the device; Fig. 4 is a view of two valve units connected to a commonauxiliary clearance, one unit being shown in plan, and the other beingshown in horizontal section on the line 4-4, Fig. 3; Fig. 5 is a detailview in longitudinal section of a portion of the valve mechanismillustrated in Figs. 3 and 4; Fig. 6 is a cross sectional view on theline 6-6, Fig. 5; Fig. 7 is a further embodiment of the device, showingmechanical means for lifting valve.

All embodiments of the invention show a device arranged to besecured toa cylinder of an internal combustion engine, and to communicate with theclearance space within the cylinder.

In the embodiment of the invention illustrated in Fig. 1 of thedrawings, the reference numeral 1 designates an auxiliary clearance, orexpansion chamber, which communicates with the interior of the cylinderby way of passage 2. Controlling the passage 2 from the cylinderclearance is a valve 3 having a seat 4: within the passage.

It is necessary, in order that a smooth distribution of the explosiveforce be obtained, that the valve. should be maintained in its openposition during a sufficient portion ofthe power stroke to permityurcssure, which has been built up in the auxiliary clearance duringcombustion to do work upon the engine piston pressure within. thecylinder tends to drop.

It is necessary that the valve means c0ntrolling communication betweenthe clear ance space of the cylinder and the auxiliary clea 'ance, bemade exceedingly sensitii e, or

be positively actuated for opening at the proper instant. It is obviousthat it the valve is not lifted before the combustion in the cylinder iscomplete, the auxiliary clean Speed of valve lifting-is therefore aprime requisite in a device of this general character; and it isnecessary in order to secure the desired results that the valve shouldbe hited from its seat within a few ten thousandths of a second from theinstant ofignition. Heavily loaded valves cannot, therefore, beemployed; as they do not possess this requisite sensitivity, and devicesemploying such valves are inoperative to alleviate or damp the explosiveforce within the cylinder. It is a fact that the speed of combustion ofa charge within a cylinder is practically independent of the speed oftravel of the piston therein. The valve between the cylinder clearanceand auxiliary clearance must therefore, be lifted with great speedirrespective of the typeof engine to which the device is applied.

In the form illustrated in Fig. 1, the means for so operating the valvecomprise an electromagnet having a core 5, solenoid 6, and shrouding 7;together with means for passing an electric current through the solenoidand energizing the magnet upon the occurrence of a predeterminedpressure within theengine cylinder.

The energizing and controlling means for the magnet comprise a batteryor generator wire 8, one terminal of which is connected with thesolenoid 6, and the other to an insulated contact 30st 9, adjustable ina suitable plug 10. ne terminal of the return wire 11 0f the circuit isconnected to the solenoid, and the other to a diaphragm 12 carrying thecontact point 18 arranged to cooperate with the point 14: of contactpost 9. The inner face of the diaphragm is in communication with thecylinder side of passage 2 by way of duct 15.

The diaphragm 12 is made of such rigidity, and the contact point 1 1 maybe so adjusted relatively to contact point 13 that the diaphragm 12 willbe forced outwardly a sufiicient distance to make contact between thepoints when the pressure communicated to the inner face of the diaphragmfrom the cylinder, by way of passage 2 and duct 15, reaches a certainpredetermined point. This point must be above the pressure caused bycompression within the cylinder. The cir cuit is completed by thecontact of the points 13 and 1 1, and the magnet energized to raise thevalve 3 from its seat a in the valve body. The arrangement described iscapable of lifting the valve within but few ten thousandths .of a secondfrom the instant at which the predetermined pressure is reached.

When the valve 8 is lifted, it is guided by its stem 16, which extendsinto a guiding recess 17 in the lower extremity of the core 5 of themagnet. lVhen fully lifted, the valve lies in contact with a bushing 18,of

' brass or other non-magnetic material, which may preferably be providedto extend down wardly beyond the core 5 so that the valve does not comeinto actual contact with the core 5 or shrouding 7.

Upon a lowering of the pressure within the cylinder below thepredetermined point, the diaphragm will spring back to break the contactbetween the contact points 13 and 1 1, thus deenergizing the magnet andpermitting the valve 3 to fall back upon its seat 4.

here engine speeds are high, means may be provided to return the valvepromptly to its seat after the solenoid has been deenergized. Such meansare illustrated in Fig. 2 of the drawing which shows a modification ofthe construction illustrated in Fig. 1, and comprise a leaf spring 19held by posts 20 on the upper surface of the shrouding T of the magnet.in this modified construction a bumper post 21 extends completelythrough the longitudinal center of the core 5 of the magnet, and issecured to the spring 19 by suitable means such as the nut 22. It is tobe understood that the spring 19 is for the purpose of returning thevalve quickly to its seat, and that bumper post 21 and spring 19 retardtravel of the valve during the extreme portion of its upward movementonly.

In the embodiment illustrated in F 3 and 1 of the drawings, a valve 3controls communication between the clearance of an engine cylinder andan auxiliary clearance or expansion chamber 1. In this form also, thealve is arranged to be opened with great speed; but in this embodiment,the valve is lifted by preponderance of pressure in the engine cylinderover that in the auxiliary clearance, and is held open until thepressure in the auxiliary clearance drops below a predetermined point.

lrieans are also provided for holding the valve open, after ithas beenraised by the preponderance of cylinder pressure, during a considerableportion of the power stroke. Such means comprise a locking rod 23, F 6,having thereon a head 24- arrangcd to frictionally engage the stem 25 ofthe valve 3" when the valve is in its lifted position. The locking rod23 is secured to a diaphragm 26 held in position in valve body 27 by asuitable retaining ring, by having a screw threaded engagement in a boss28 on the diaphra gm 26. The inner face of diaphragm 26 is incommunication by way of duct 29 with the auxiliary clearance side ofpassage 2.

The operation of the valve in this embodiment of the invention is asfollows: Valve 3*, during combustion of the charge within the enginecylinder, starts to rise at the instant the pressure within the cylinderreaches a point of preponderance over that within the auxiliaryclearance chamber. Upon lifting of the valve, and consequent increase ofpressure within the auxiliary clearance, the diaphragm 26 is forcedoutwardly, bringing the head 24 of locking rod 23 into frictionalengagement with valve stem 25. The diaphragm 26 thus serves to maintainthe valve in open position during a portion of the power stroke in thecylinder, thus permitting pressure in the auxiliary clearance to do workupon the engine piston. Upon a drop in the pressure in the auxiliaryclearance below a predetermined point, which may be determined by the deree of rigidity of diaphragm 26, the diap ragm moves inwardly todisengage head 24 of rod 23 from the stem 25 ofthe valve 3. It isunderstood that when the auxiliary clearance pressure has dropped tothis point, the pressure within the cylinder has dropped still fartherso that it does not oppose the closing of the valve. The diaphragm 26,mustbe of such a predetermined degree of rigidity that the valve 3*willbe permitted to close before the pressure in auxiliary clearancechamber 1 has dropped to a point as low as the pressure caused by thecompression in the cylinder.

A spring 30 is preferably arranged in a recess in the body of the device27 to bear againsta bumper post 31, which is in line with the stem 25 ofthe valve. A space is provided between the extremity of bumper post 31and the extremity of the valve stem 25 so that the valve stem contactsthe bumper post and compresses spring 30, only as the valve approachesthe extreme limit of its upward travel. The spring acts, therefore,

merely to assist quick reseating of the valve upon a sufiicientdrop inauxiliarychamber pressure. It will thus be seen that the valve iscompletely unloaded so far as its unseating is concerned and that itfree to respond instantaneously to the operative variations in pressure.The auxiliary clearance chamber is preferably provided with a heatinsulating lining 32, so that loss of heat, due tothis-increasedradiating surface, is minimized. As shown in Fig.4:of thedrawings, the auxiliary clearance chamber is preferably made common toall the cylinders of an engine, when theengine to which the device isapplied is of the multi-cylinder type. In such case, the auxiliaryclearance has i a valve controlled communication with the clearancespace ofeach of the cylinders. It is to be understood that the commonauxiliary clearance may be applied equally well in connection with anyof the embodiments of the invention; and also, that the scope of theappended claims is not to be limited to the use of the device witheither a single cylinder or a multi-cylinder engine.

In Fig. 7 of the drawings, th-re is illus trated a further embodiment ofthe device in which mechanical means are provided for lifting thevalvecontrolling communication between the, auxiliary clearance space 1and the clearance space within the engine cylinder. In this embodiment,the valve 3 has a stem 33 carrying a collar 34 on which bears a spring35 for normally maintaining the valve in its closed position. The valve"is lifted at the desired. intervals by means of a cam 36 cooperatingwith a roller 37 on the extremity of the valve stem or push rod 33. Thevalve 3 is maintained in its open position during a portion of the powerstroke in the cylinder by means of the cam 36 which is designed to bearagainst the roller 37 for an appreciable interval of time. As

soon as the cam has passed the valve stem, spring 35 serves to restorethe valve to its seated-position. The cam 36 iscarried b the main or anauxiliary cam shaft 38,whic 1 tive in its operation It does, however,present the disadvantage that itsoperation is governed by the pistonspeed of the engine, and not by the speed of combustion.

In all embodiments of the invention, the device functions to secure thesame general effects. Upon lifting of the valve during combustion in thecylinder, the gas already in the auxiliary clearance is furthercompressed and thepressure in this chamber is raised to a relativelyhigh point. pressure within the cylinder drops, this pressure within theauxiliary clearance acts uponthe piston in the cylinder to do workthereon, the valve remaining lifted during this interval. The valve isclosed before the pressure in the auxiliary clearance has beencompletely dissipated. In all forms of the device the regulation of themeans for opening the valve between the engine cylinder and theauxiliary clearance chamber, or for holding this valve open, is suchthat a pressure above that caused by compression in the engine cylinderis maintained in the auxiliary clearance chamber at all times duringnormal operation of the engine.

'i\l.l embodiments of the inventlon pro vide constructions which attainthe high speed of valve lifting requisite in order to render the deviceoperative.

hat I claim is: i

1. In conjunction with an internal combustion engine an auxiliaryclearance chamher in communi-ation with the clearance space of a.cylinder, and unloaded valve means controlling such communication, saidvalve means being arranged to .open only upon the occlu'rence within thecylinder of a pressure higher than that caused by compression therein.

2. In conjunction with an internal co111- bustion engine an auxiliaryclearance cha1nher in communication with the clearance space of acylinder, valve means controlling such communication, said valve meansbeing arranged to open only upon the occurrence" within the cylinder ofy a pressure As the i ments previously described in that it isposihigher than that caused by, compression therein; andimeanscomprising a diaphragm controlling the reseating ofsaid valve means Ibustion engine an auxiliary clearance chamber in communication with theclearance space of a cylinder, unloaded valve means controlling "suchcommunication, and independent means for maintaining such valve meansinopen position during a portion of the power stroke in the cylinder.

5. In conjunction with an internal combustion engine an auxiliaryclearance chamber in communication with the clearance space of acylinder, valve means controlling such communication and maintained inclosed position during compression within the cylinder by apreponderance of pressure within the auxiliary clearance, andindependent means comprising a diaphragm for maintaining said valve inopen position during existence in the auxiliary clearance L chamber ofpressure above a predetermined point.

6. In conjunction with an internal coinbustion engine an auxiliaryclearance chamber in communication 'with the clearance space of acylinder, unloaded valve means controlling such communication andarranged 'to be lifted by preponderance of cylinder pressure overauxiliary clearance pressure; and independent means in communicationwith said auxiliary clearance and arranged to maintain the valve whenlifted in open position until auxiliary clearance pressure drops below apredetermined point.

7. In conjunction with an internal combustion engine an auxiliaryclearance chamber in communication with the clearance space of acylinder, unloaded valve means controlling such communication andarranged to be lifted by prepond rance of cylinder pressure overauxiliary clearance pressure; a locking member arranged to con- 7 tactthe valve means for maintaining such valve means in open position, and adiaphragm in communication with the auxiliary clearance chamber andarranged to release said valve means upon a drop in auxiliary clearancepressure below a predetermined point'.

8. In conjunction with an internal combustion engine an auxiliaryclearance chamber in communication with the clearance space of acylinder, unloaded valve means controlling such communication, anelectromagnet, and yielding'means in communication'with the clearancespace of the cylinder and arranged to make and break the circuit of saidmagnet for lifting and releasing said valve means. I

9. In conjunction with an internal combustion engine an auxiliaryclearance chamber in communication with the clearance space of acylinder, valve means controlling such communication and maintained inclosed position during compression within the cylinder by apreponderance of pressure within the auxiliary clearance, and yieldingmeans for maintaining said valve in open position during existence inthe auxiliary clearance chamber of pressure above a predetermined point.

1.0. In conjunction with an internal combustion engine an auxiliaryclearance chamber in communication with the clearance space of thecylinder, unloaded valve means controlling such communication andarranged to be lifted by preponderance of cylinder pressure overauxiliary clearance pressure; a diaphragm in communication with saidauxiliary clearance chamber, and a rod on said diaphragm arranged totrictionally engage said valve means for maintaining the latter in openposition.

11. In conjunction with an internal coinbustion engine an auxiliaryclearance chamber in communication with the clearance space of acylinder, unloaded valve means controlling such communication. saidvalve means being arranged to open only upon the occurrence within thecylinder of a pressure higher than that caused by compression therein,and means responsive to pressure 'ariations for controlling theresenting of said valve means.

12. In conjunction with an internal combustion engine an auxiliaryclearance chamber in communication with the clearance space of acylinder, unloaded valve means controlling such communication, saidvalve means being arranged to open only upon the occurrence within thecylinder of a pressure higher than that caused by compression therein,and resilient means arranged to quicken the resenting movement of Filldvalve means.

13. In conjunction with an internal combustion engine an auxiliaryclearance chamber in communication with the clearance space of acylinder, valve means controll ng such communication, said valve meansbemg arranged to open only upon the occurrence within the cylinder of apressure higher than that caused by compression therein: meanscomprising a diaphragm controlling the reseating of said valve, andleSllltllt means arranged to bear against said valve means in fully openposition of the latter and to quicken the resenting movement ot thevalve means.

14. In conjunction with an internal conr bustion engine an auxiliaryclearance cha1nher in communication with the clearance space of acylinder, unloaded valve means controlling such communication,independent means for maintaining said valve means in open positionduring a portion of the power stroke in the cylinder, and resilientmeans arranged to quicken the reseating movement of said valve means.

15. In conjunction with an internal combustion engine an auxiliaryclearance chamher in communication With the clearance space of acylinder, unloaded valve means controlling such communication, saidvalve means being arranged to open only upon the occurrence Within thecylinder of a pressure higher than that caused by compression therein,means responsive to pressurevariahand.

BRYANT BANNISTER. lVitnesses FLORENCE F. SCHWARTZ, Gianrm W. ALsroN.

